If it will be also $1000 than obviously yes. But no one knows what it will sell for. Hence, waiting six months is worth close to $100. It's your call.
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I think a 6 month of upgrade is worth more like! 150..
Only iphones have such major hype that casues them to be under stock and sell at a high right when they first are released, also they usually are first releases in the USA so that gives them the international benefit over other phones (like the BlackBerry was prior released not in the USA so the time it was available in the USA it lost its high resale value)
But nothing is guaranteed the 5s could me minimal upgrade that it won't be as hot as the 5 and also By now Apple should have learned to manufacturer more at the time of release